A prober has been known as a substrate inspection apparatus that inspects electrical characteristics of semiconductor devices, for example, a power device or a memory, formed on a semiconductor wafer (hereinafter, simply referred to as “wafer”) serving as a substrate.
The prober includes a circular plate-shaped probe card having a multiple number of probe needles; and a stage which mounts the wafer thereon and freely moves up and down or from side to side. As the stage mounting the wafer thereon is moved toward the probe card, the respective probe needles of the probe card are allowed to be brought into contact with electrode pads or solder bumps of the semiconductor devices. Then, by allowing an electric current for inspection to flow to the electrode pads or the solder bumps through the respective probe needles, the electrical characteristics of the semiconductor devices are inspected (see, for example, Patent Document 1).
In the prober, the probe needles of the probe card are repeatedly brought into contact with the respective electrode pads, so that tips of the needles may be abraded. Therefore, it is necessary to regularly polish the needle tips of the probe needles.
Typically, the needle tips of the probe needles are polished by a needle-tip polishing device provided at a side of the stage. To be specific, as depicted in FIG. 9A, a needle-tip polishing device 81 provided at a side of a stage 80 is fixed to a the stage 80 by a stay 82, and the stage 80 is moved in a horizontal direction to arrange the needle-tip polishing device 81 to face probe needles 84 of a probe card 83. A wide area polish plate (hereinafter, simply referred to as “WAPP”) 85 constituting an upper portion of the needle-tip polishing device 81 is moved toward the probe card 83 by a hydraulic cylinder 86 of the needle-tip polishing device 81, and the stage 80 is also moved toward the probe card 83 (FIG. 9B) to bring a needle-tip polishing sheet (wrapping sheet) 87 provided on a needle-tip polishing surface of the WAPP 85 into contact with needle tips of the respective probe needles 84.
Recently, an increase in a diameter of a wafer has been considered. However, as a probe card is increased in size, the bending of the wafer or the probe card is increased. In this case, in order to reliably bring the probe needles of the probe card into contact with the electrode pads of the semiconductor devices, a load of the stage to press the wafer to the probe card needs to be further increased.
Patent Document 1: Japanese Patent Laid-open Publication No. H07-297242
When the needle tips of the probe needles are polished, the stage is also driven as described above. Therefore, as the load of the stage to press the wafer against the probe card is increased, a load applied to the WAPP to press the wrapping sheet of the WAPP against the probe needles is also increased. At this time, a reaction force corresponding to the load applied to the WAPP is received by the respective probe needles. The reaction force is increased since it is proportional to the load applied to the WAPP. As a result, a hydraulic cylinder of the needle-tip polishing device cannot respond to the increased reaction force, so that it becomes difficult for the hydraulic cylinder to press the wrapping sheet of the WAPP against the probe needles.